Blood analysis is typically a preferred choice in most laboratory tests for diagnosis and disease monitoring. However, assays of blood are seldom performed at the bedside, and it may be hours or days before results are known. When a subject's status is rapidly changing, and supportive and therapeutic maneuvers are underway, such as in an intensive care unit, real-time data on the function of the cardiovascular, respiratory, and other systems is of critical importance for distinguishing salutary from counterproductive actions. Non-invasive techniques involving body temperature, respiratory rate, and pulse rhythm have been historically known to be informative parameters for diagnosing, staging, and monitoring disease. Ancient physicians also recognized the diagnostic utility of smelling the exhaled breath for tell-tale aromas, such as with hepatic or renal failure. For some conditions, including, but not limited to, bacterial infections, malaria, diabetes, cystic fibrosis and cancer, analysis of exhaled breath may be a sufficiently accurate test that may help in clinical decision making. Thus, a means to analyze exhaled breath of a subject (and identify certain gaseous compounds in them) with sufficient sensitivity and discrimination may be hugely beneficial in diagnosis and treatment of certain disease states. In view of the above, a cost-effective, compact and accurate automated breath analyzer that can be used at the point-of-care is highly desirable.